NOTE: Here's an important new study that reviews the state of the science regarding GM food safety.

EXCERPT: It is worth mentioning that most of the studies demonstrating that GM foods are as nutritional and safe as those obtained by conventional breeding, have been performed by biotechnology companies or associates, which are also responsible [for] commercializing these GM plants....

Scientists know quite well how different may be the information published in reputed international journals, which has been submitted to peer-review processes, from those general comments/reports not submitted to this selective procedure....

Especially critical is the recent review by Dona and Arvanitoyannis (2009), who remarked that results of most studies with GM foods would indicate that they may cause some common toxic effects such as hepatic, pancreatic, renal, or reproductive effects, and might alter the hematological, biochemical, and immunologic parameters.
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A literature review on the safety assessment of genetically modified plants
Jose L. Domingo, Jordi Gine Bordonaba
Environment International 37 (2011) 734 742
http://bit.ly/ge44Uu

Abstract
In recent years, there has been a notable concern on the safety of genetically modified (GM) foods/plants, an important and complex area of research, which demands rigorous standards. Diverse groups including consumers and environmental Non Governmental Organizations (NGO) have suggested that all GM foods/plants should be subjected to long-term animal feeding studies before approval for human consumption. In 2000 and 2006, we reviewed the information published in international scientific journals, noting that the number of references concerning human and animal toxicological/health risks studies on GM foods/plants was very limited. The main goal of the present review was to assess the current state-of-the-art regarding the potential adverse effects/safety assessment of GM plants for human consumption.

The number of citations found in databases (PubMed and Scopus) has dramatically increased since 2006. However, new information on products such as potatoes, cucumber, peas or tomatoes, among others was not available. Corn/maize, rice, and soybeans were included in the present review. An equilibrium in the number research groups suggesting, on the basis of their studies, that a number of varieties of GM products (mainly maize and soybeans) are as safe and nutritious as the respective conventional non-GM plant, and those raising still serious concerns, was currently observed. Nevertheless, it should be noted that most of these studies have been conducted by biotechnology companies responsible of commercializing these GM plants. These findings suggest a notable advance in comparison with the lack of studies published in recent years in scientific journals by those companies. All this recent information is herein critically reviewed.
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Final remarks
In the same line of our previous papers (Domingo, 2000, 2007; Domingo-Roig and Gómez-Arnáiz, 2000), the main purpose of this review-article was to critically revise the published scientific
literature on potential toxic effects/health risks of GM plants. It was noticed that the total number of general references on GMOs in general, and GM foods/plants in particular, found in the databases PubMed and Scopus has considerably increased between our 2006 search (Domingo, 2007) and the current one. In spite of this, the number of studies specifically focused on safety assessment of GM plants is still limited. However, it is important to remark that for the first time, a certain equilibrium in the number of research groups suggesting, on the basis of their studies, that a number of varieties of GM products (mainly maize and soybeans) are as safe and nutritious as the respective conventional non-GM plant, and those raising still serious concerns, was observed. Moreover, it is worth mentioning that most of the studies demonstrating that GM foods are as nutritional and safe as those obtained by conventional breeding, have been performed by biotechnology companies or associates, which are also responsible of commercializing these GM plants. Anyhow, this represents a notable advance in comparison with the lack of studies published in recent years in scientific journals by those companies (Domingo, 2007). The scientific community may finally be able to critically evaluate and discuss all that information, which was not possible until now. Scientists know quite well how different may be the information published in reputed international journals, which has been submitted to peer-review processes, from those general comments/reports not submitted to this selective procedure.

A relatively remarkable finding of the present review is that the published scientific literature between October 2006 (Domingo, 2007) and August 2010 (current review) on edible GM plants, concerns only to three products: corn/maize, soybeans, and rice, rice being comparatively the less abundant. We have not been able to find citations involving investigations on GM potatoes (except a review by Arvanitoyannis et al., 2008), peas, tomatoes, pepper, etc., after October 2006. A summary of experimental studies (October 2006 August 2010) concerning dietary administration of those products to various animal species is shown in Table 1. With respect to corn/maize, various studies have concluded that the transgenic varieties 1507 (MacKenzie et al., 2007), 59122 (Malley et al., 2007; Juberg et al., 2009; He et al., 2008),1507×59122 (Appenzeller et al., 2009a), 98140 (Appenzeller et al., 2009b; McNaughton et al., 2007), Y642 (He et al., 2009), and MON 88017 (Healy et al., 2008) were
  as safe
as conventional quality protein maize. In contrast, Séralini's group raised concern regarding some commercialized GM maize (NK 603, MON 810 and MON 863) (Séralini et al., 2007, 2009; de Vendômois et al., 2009). Similarly, scientific controversy is also present in relation to the safety of GM soybeans. While it has been reported that 356043 (Sakamoto et al., 2007) and 305423 (Delaney et al., 2008) soybeans were as safe as conventional non-GM soybeans, some authors are still concerned by the safety of GM soybeans and recommend to investigate the long-term consequences of GM diets and the potential synergistic effects with other products and/or conditions (Malatesta et al., 2008a,b; Cisterna et al., 2008; Magaña-Gómez et al., 2008).

In the period here revised, October 2006 August 2010, a few reviews on health risks of GMfoods/plants have been also published (Dona and Arvanitoyannis, 2009; Magana-Gomez and de la Barca, 2009; Key et al., 2008). In general terms, all these authors agree in remarking that more scientific efforts are clearly necessary in order to build confidence in the evaluation and acceptance of GM foods/plant by both the scientific community and the general public. Especially critical is the recent review by Dona and Arvanitoyannis (2009), who remarked that results of most studies with GM foods would indicate that they may cause some common toxic effects such as hepatic, pancreatic, renal, or reproductive effects, and might alter the hematological, biochemical, and immunologic parameters. These authors also concluded that the use of recombinant GH or its expression in animals should be re-examined since it has been shown that it increases IGF-1 which, in turn, may promote cancer. A harsh response to that review was recently published in the same journal (Rickard, 2010). This is indeed only an example on the controversial debate on GMOs,which remains completely open at all levels.

Finally, we would like to indicate that the review on allergenicity of GM plants has not been included herein. European legislation stipulates that GMOs have to be monitored to identify potential adverse environmental effects (Reuter et al., 2010). The European Food Safety Authority (EFSA) has recently published a Scientific Opinion regarding assessment of allergenicity of GM plants and microorganisms and derived food and feed (EFSA, 2010). Detailed information on this important issue is available at
http://www.efsa.europa.eu/en/scdocs/scdoc/1700.htm.